1. Field of the Invention
The present invention relates to an RFID (Radio Frequency Identification) tag suitable to an environment recognizing individual items, capable of being attached to items of various dielectrics including a metal item.
2. Description of the Related Art
An RFID system of a UHF (Ultra-High Frequency) band is a so called highlighted information recognition technology over an RFID system of a HF (High Frequency) band, due to an information transmission ability of high efficiency.
An RFID system of the UHF band is comprised of an RFID tag storing item-related information and a reader for recognizing the RFID tag. Each of the tag and reader uses an antenna, and transceive given information via a medium of electric wave. In particular, a passive-type tag is comprised of an antenna and a tag chip, free from a battery, and capable of being used with inexpensive price.
A passive-type tag of an UHF band principally determines an item recognition characteristic of an entire RFID system, and is in particular, dependent on a complex conjugate matching of a tag antenna with a tag chip, a radiation pattern of a tag, and a tag chip performance, for capability of the tag.
The tag developed based on such ability may include a tag having an operating frequency of 860˜960 MHz for availability in a world-wide level, a tag holding a good quality of recognition characteristic for various dielectric constant's items, and a special-type tag designed possibly to use in metal items.
However, the tags have been generally developed for the purpose of wide-usability in a use environment, and tags having an improved recognition area by adjusting a radiation characteristic of tags itself need further development.